<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>盒子模型</title>
  <style>
    div {
      width: 300px;
      height: 200px;
      border-width: 5px;
      border-style: solid;
      border-color: pink;
      border-top: #dc3545;
    }
  </style>
</head>
<body>
    <div></div>
</body>
</html>